


Heat

by AQueenWithoutRules



Series: The Undertale Brothers, and How They Came to Be [5]
Category: Undertale (Video Game)
Genre: Angst, Begging, Dom Papyrus, Even though they aren't doing the do at that point, First Time, First time either of them does the do, Fontcest, Goopster, Hurt/Comfort, Incest, M/M, NSFW, Old scars, Papyrus is in heat, Relationship Issues, Relationship Problems, Skeleheat, Soul Sex, Sub Heat, Sub Sans, Underage tag bc smol suffering skeles, dom heat, first heat, heat - Freeform
Language: English
Status: Completed
Published: 2017-02-03
Updated: 2017-02-06
Packaged: 2018-09-21 17:19:58
Rating: Mature
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply, Underage
Chapters: 3
Words: 5,952
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9559409
Author URL: https://archiveofourown.org/users/AQueenWithoutRules/pseuds/AQueenWithoutRules
Summary: Papyrus enters his heat without knowing what it is, and discovers things he really didn't want to see.





	1. Chapter 1

**Author's Note:**

> I'm progressively becoming worse at summaries I think but oh well  
> This is meant to take place after 'Tradition' but before 'Why So Tense?'  
> When Paps actually finds out what the heck sex and junk is  
> Like "OH YOU CAN USE YOUR TONGUE FOR THIS COOL"  
> Anyway that was dumb  
> This will still probably have another chapter if I myself am not dumb and actually finish a project for once wowww

Papyrus woke suddenly. He was hot... so hot... did he have a fever? He felt his head, frowning. No... he did not feel weak. Not at all. If anything, he just felt more energized. A lot more energized. He wanted to... do something... but... he wasn't certain what exactly. He sat up and moved to the edge of his bed, putting his head in his hands and bouncing his leg impatiently. He felt restless. 

What did he want...?

Sans. He wanted his brother. He wanted his mate. 

He rose, his chest growing tighter with... what? Impatience? But for what?

He walked out of his room, face covered with a natural scowl at this point, panting slightly, and face flushed. He glanced at the clock on his wall and winced. He was two hours late for work. And he hadn't even called to say he wouldn't be coming!

A wave of the heat rushed over him and his mind went blank for a moment, resuming only to thoughts of Sans.

Sans would know what to do. His brother knew everything.

He barged into the skeleton's room, a bit more aggressively than normal, and immediately berated himself for it, catching the door as it rebounded from hitting the wall and apologizing softly but profusely to the object. His eyes then scanned over the room, resting on the lump on the bed.

It only stirred slightly, lifting its head slowly and rubbing its eyes. “b-bro? what-”

Before he could even finish, Papyrus had lifted him up from the bed to chest level and smashed the skulls together in a skeleton kiss. This was what he wanted. To be closer to Sans. After almost a full minute of stillness in the position, Sans started squirming and Papyrus laid him back down onto the bed, hovering over him, continuing to pant and flush. Sans didn't look much better, but at least he didn't look as out of it as Papyrus felt. His face, blue, his eyes, black. He panted as he lay on the bed, eyelights slowly returning and shimmering, blue and gold. Such pretty colors. Sans made such an adorable image. He wanted to... destroy it. He wanted those eyes to beg him for more as he... as he what...?

Agh, he was so hot--!

He smashed their teeth together again. His brother would take some of this heat of his, and it wouldn't be so impossible to bear. His tongue summoned on its own and he didn't understand why until he saw the desire in his brother's eyes directed toward the glow. He paused for a moment before making a sudden decision and licking downward from his face towards his neck.

Those sounds...!

His brother let out a moan that only increased the heat. And yet... he wanted more of it. He licked all along the neck, forcing those sounds out of him until his brother pushed him away.

“w-wait, pap-pap, do you even...” He was panting too hard to even speak clearly, and Papyrus was already getting impatient again. He leaned back in, licking down even lower towards his sternum.

“paPYRUS WAIT-” The panic in his voice gave the younger skeleton pause, and he leaned back despite the strong desire to continue. He didn't ever want to betray Sans' trust, even if he wasn't thinking clearly at the moment.

Sans took a moment to catch his breath before looking Papyrus up and down, simple as the other now sat on his legs. Why was Papyrus acting like this...? He didn't quite understand why he had suddenly changed. After a moment of thought, the smell in the air came to his attention. It smelled like... caramel? But that was a treat only for the rich. Certainly not something to be found in their house... And then there was the heat. It emanated from the other skeleton, and Sans was sure that if they went outside he would be visibly steaming. What would...?

Oh. Right.

Their heats.

He mentally face-palmed himself for not realizing any sooner. That's why he was suddenly acting like this. He was in heat. Sans himself had read about heats, but never experienced one. After all, they only happened when you were with a partner that you trusted completely. Sans would have been overjoyed! 

That is, if Papyrus himself knew what was happening to him.

The skeleton in question was staring at where his ribs were, toying with his ilium subconsciously. Honestly, it was a bit distracting, but he knew that probably wouldn't be the worst of it today.

Papyrus' first heat. Amazing the other had gotten it before him, considering the four year difference in age. Although, Papyrus always had trusted easier than him. And Sans had only ever had eyes for Papyrus. He had read that the first heat was always the most intense. They only occurred once a month with trust. That thought scared him a bit. Whatever they did today, he would have to do the same in only a month. That is, as long as Papyrus... he sighed. Did Papyrus really even want to be with him? Was he really the best for him and this situation?

“Sans...” His brother let out a breathless whine. “I want to... do something to you... please... let me touch you... I can't hold it back much longer.” He rubbed their pelvises in an attempt to move closer and his eyes began to glimmer. He looked like he was near tears. Although he had been dominant at first, entirely so, he had been neglected his need. And on the first heat...

Sans sighed again. It didn't matter if he was the best. Papyrus had chosen him, and he would be damned if he neglected his brother when he needed him most.

“papyrus.” He made no reaction to his name, other than moving his shimmering eyes in an attempt to look at Sans'. He tensed slightly before forcing himself to relax and continue. “you're in a process called 'heat.' it happens to all monsters, it's completely natural...” Another pause. “it will also happen every month for as long as you are with me. there are... many ways to take care of it.” At this point he found it hard to stay relaxed and his shoulders remained tense as he tried to be calm.

“Like what? How do I stop this?” 

“y-you... umm...” He shook his head, and, hands shaking, reached out to Papyrus. “it would be e-easier to just sh-sh-show you... s-summon your s-soul.”

Papyrus, ever trusting, did so without argument, eyes locked on Sans' own. He didn't quite understand all of this, but he knew that those quivering eyelights and shaking voice made him feel extremely good.

The upside-down, dimly lit orange heart seemed to shine brighter than Papyrus had ever seen it, especially once Sans took it into his shaky hands. He looked up at the other for confirmation that he could continue. “Please...” That seemed to be all he needed, and he ran his right hand over it, using the left to keep it steady.

The jolt that went through the taller almost caused him to fall over on top of his brother, but he caught himself early on and simply ended up bucking his hips against Sans', causing a hiss of pleasure from Sans and another strange new feeling for Papyrus. He stared at Sans intensely before doing it again, watching him for a response. He received more than he'd asked for.

The other's hiss had seemingly been a release of air through a wide open mouth. His soul skipped a beat as he watched the reaction. Sans was barely able to hold onto the soul and so gripped it tighter through his reaction, close to his chest and own soul. It sent even more pleasure down Papyrus' spine, but that wasn't the main point. The main point was Sans' face. One of his eyes closed and the other was lidded. The mouth, now wide open, drooled a slight bit and revealed his blue tongue inside. The face flushed a bright blue, lighting up the covers. The lights turned into small blue hearts for only a moment and he could barely contain himself. He wanted to see more of that. To see those hearts more often. He wanted to hear more of those sounds. 

He did it again.

And again.

Until soon, he was doing it in a constant rhythm.

But still.

Still.

He wanted to see if he could get more.

Sans was distracted entirely at that point, focusing only on keeping the soul in his grip and the point of pleasure Papyrus had created.

So he naturally didn't notice the skeleton's hand moving from the bed until it had already pulled up half of his shirt.

He let out a panicked shriek, pleasure suddenly turned to immense fear as he moved one of his hands from the soul and attempted to push his shirt back down, but it was too late. 

A moment of dead silence filled the room, and Sans' eyes filled with tears and streaked down his face. Why had he ever thought this relationship was a good idea. Here he was, beneath his brother, and one of his largest secrets towards him was revealed. He allowed the other to push the shirt up the rest of the way, limp. It didn't matter anymore.

The long scar, stretching from his clavicle and all the way across his ribs, shown to Papyrus as his brother began crying silently. For a long moment he simply stared at it, running his fingers across it without truly touching it. It had to have happened years ago, maybe even when they were just children. Who would inflict this kind of wound on a child? The heat in his chest died down. It didn't leave entirely, but the sick feeling in his mouth certainly quelled it a bit.

“i-i'm sorry,” Sans' speaking interrupted his thoughts and he looked at the small skeleton under him. Tears had created a trail down his face, and he brought his hand up to cover it all, shamefully hidden. “i'm so sorry, it's so disgusting, i know, and i hate it, and i don't even know why you ever wanted to be with me, why you even bother, and i'm so useless, i'm scarred, and you deserve so much better, s-so much better-”

“How.” Papyrus stated it simply, cutting his brother off with an undertone of rage and no area for argument.

The tone only made Sans shake more, but he pulled his hand down from his tear stained eyes and mumbled into it with a sob. “i can't tell you.”

Papyrus snapped at the words. His soul de-materialized in a bright flash of white and he stood angrily. The tension of the 'heat' lingered, but it was deeply locked away now. He was almost too enraged to feel it. Almost. 

He stormed out of the room without glancing back.


	2. A Promise I Will Always Keep

**Summary for the Chapter:**

> Sans' past with Gaster. Not exactly what you're thinking.

**Notes for the Chapter:**

> This chapter was getting really long so I split it ;w;  
> dON'T HATE ME AAA  
> N E XT CHAPTER IS GONNA BE SMUTTY THO  
> PROBABLY
> 
> Warnings- Gore, don't read if you can't!   
> Nothing sexual, but children are suffering

Sans lay in his bed, feeling like crap. Of course he'd screwed things up. He always did. He sat up and leaned against the wall, consideration on his face for a moment before he stripped off his shirt and looked at the scar. He hated it. The brownish discoloration showed clearly when compared to the pure white of the rest of his bones. He ran his fingers over it, trying to distract himself from the thoughts of how it had come to be there in the first place, but to no avail. The thoughts flooded his mind anyway in a dreamlike quality... Or, in this case, more of a nightmare he could never escape from.

-

Sans choked on the dust in the air, covering his face with his sleeve. Eight years old, he searched. Papyrus... please! Where was his little brother...?

He'd dropped him in the fall. Oh stars, he'd dropped him! He had to find him, he had to-!

A flicker of white crossed over his vision and he sprinted past it. He didn't want to look at it, didn't want to, didn'twanttodidn'twanttodidn't-

It had other plans. 

The white mass grabbed one of his feet and pulled him backwards toward it, latching onto him. The goop fell over him, burying him in the thick liquid of its body. He closed one of his eyes as the honey-like substance fell over it, pulling away from it as well as he could. His little brother, where- where was-?!

There! 

The toddler was crying, crawling towards Sans, and his efforts to get away from the... the... THING, renewed tenfold.

He had to protect his brother.

His bones erupted from the ground in an explosion of power. The small attack, a measly 5 at his current LOVE, did little to the thing, but it stunned it and he took full advantage of the opportunity, ripping himself away and scanning once more for Papyrus-

Only to freeze.

Oh stars.

What had he DONE?!

Papyrus' neck was pierced through, with one of HIS bones, barely hanging on. This wasn't what he'd wanted. This wasn't what he'd wanted at all. He ran towards the other, panicked, tears falling and fear coursing through every bone in his body.

His little brother looked at him with blank eyesockets before he fell unconscious, and Sans hurriedly unsummoned the bone in his neck.

Why had his magic gone out of control?! Not something to worry about right now, he had to focus on Papyrus. He caught the toddler as he fell, inspecting the damage entirely. 

It had completely pierced through, and although his attacks wouldn't normally do any damage at all, to a child this small...

He thought quickly. This was so important, why were no ideas coming to his mind at THIS TIME, of all the times it COULD HAVE?!

But then, an idea occurred to him.

He'd only read about it, but as Papyrus' life slowly faded, he decided it didn't matter, he HAD to TRY.

To heal someone with your soul.

Your magic had to be similar, or linked in some way, but he guessed that that wasn't a problem. They were BROTHERS, after all.

You also had to love the other quite a bit. Not the violent love, but true love.

Again, not a problem.

And you had to summon your soul.

He supposed not everything could be perfect.

Sans hadn't ever even been in a battle. He'd never summoned his soul before, unless when he was born counted, as monsters' bodies formed around their souls' magic as the were created.

He had no idea what to do.

He considered it as quickly as he could. Souls... Souls came when you were hurt, right? Papyrus' had appeared at this point, at least, and they always seemed to appear during battles...

He looked down at his chest, laying his brother down softly.

All he needed was something sharp.

He grabbed one of the lab's scissors on the table near him. He'd make this quick, then.

In a swift motion, he raised the scissors above his head and plunged them into his shoulder with his left hand, letting out a scream of pain.

Nothing.

Gritting his teeth, he dragged it downward, using his other hand to force it through all of the bones instead of skirting over them. Tears ran freely now.

Still nothing.

He finished dragging it all the way through his limbs. He was almost unconscious, but he couldn't stop now... He had to... had to help Papyrus...!

But...

His soul didn't arrive.

Sans collapsed, curling around his brother, letting out sobs. At least they'd die together. 

He had failed. He had failed as a sibling, and...

He had failed as a son.

The child looked to the amalgamation. It had recovered. It moved toward him strikingly fast. Of course it wouldn't want to lose its 'prey' again.

Not that he would be able to do anything even if it had moved slowly.

It picked him up, and he cried, reaching out as he realized Papyrus wasn't coming with him.

No! Nonononononono- He, he HAD to die by his brother's side, he HAD to-!

Sobbing as it turned him towards it, all he did at this point was hold on.

It was all he could do.

He looked into the face of the creature. The black, hollow smile stretched across its face.

Sans had always loved his father's scars. They managed to make him look even more dignified as the scientist. 

But now they simply gave the creature a haunting look. It was as if everything that had been admired about his father was turned on its head, and Sans stared at the result.

It was hunched, so much different than his father's tall and straight appearance. His hands were simply dripping white goo, his labcoat the same.

He gave off the impression of a fallen angel.

Sans' head rolled to the side slowly. He was dying, he realized. His soul appeared, upside-down and a pretty blue. He'd say 'better late than never,' but in this case he thinks he would have preferred never.

At least then he wouldn't have to suffer more, realizing a bit more time would have allowed him to save his sibling.

The monster brought him over to a desk quickly, laying him on a table near it. He distantly wondered where they were going. It made an attempt to grab something, but he heard a hiss. It reminded him of his father's curses when things weren't going well.

He felt a slight pain in his arm, then sudden agony all over his body. He screamed, body arching off the table, but the creature must have attached restraints at some point, unnoticed by his numbing body.

He almost preferred the numbness.

The shocking pain caused him to look down at what prompted it, keeping one eye scrunched shut tightly. The creature was looking down at him with an unsure look on its face, impatient. His soul remained and... what was that?

His shirt was red in the front.

The creature again let out a hiss. It sounded like static, but also some kind of language...?

Whatever it was, Sans couldn't understand it.

His confusion must have shown on his face as the other quivered in its place in some form of acknowledgment, but it looked down with an anxious expression.

The haunting smile returned quickly though. It seemed to be trying to encourage him.

The pain had faded to a dull ache. He still wasn't entirely trusting of it. And he only know one way he might trust it more.

*CHECK  
*REDACTED  
*IT'S SORRYORRY-S-SOR-

The creature seemed to glitch out of the world for a moment before a look of panic crossed its face and it un-did his restraints, letting out anxious hisses and staring pointedly at him, looking over to the small limp body still on the floor.

Sans took the hint easily. His soul still summoned, he ran over to the body, hovering over it, afraid to touch. “can't you do what you did with me?” Redacted's body shivered before it shook its head quickly.

Sans went back to his original plan immediately. He didn't have the time to waste on arguing why.

He gently grasped at Papyrus' soul, pulling it closely to his own. “don't worry, bro. it's all gonna be alright.” He reassured the child whose feet were beginning to dust, not even sure of it himself.

He held his breath for a moment before closing his eyes and smashing their souls together. 

The pain over his own body was unexpected, but after a moment of paralyzed thought he realized it made sense. After all...

Papyrus was in much worse shape than he was at the moment.

He could FEEL the weakness in the other's soul... and all he wanted to do was fix it.

He poured his energy into the small soul. He would bring Papyrus back.

No matter what it took.

He gasped for breath as he felt his energy leaving him, but it was okay.

Just as long as Papyrus was safe.

His life didn't matter.

Especially since he had caused this in the first place.

Because even as he felt himself getting weaker and weaker...

He felt his brother coming back to him.

And that made it worth it.

That made it all worth it.

So of course, even after all of his stats went down to 1, he continued pushing.

 

Gaster had fallen into his own creation, his Determination Extraction Machine.

He had simply been trying to test a human soul in the machine for the first time. He'd wanted his sons with him for this momentous occasion. Sans had been helping him for almost the past year to simply keep Papyrus entertained while he worked, sometimes by reading a book on physics to the small skeleton. He'd chuckled, not the choice he would have chosen.

And that day, he'd fallen.

They'd gotten some determination out of it, although he used it on Sans after the facts.

He didn't blame his son's reaction.

Not after what he had become.

“REDACTED.”

Censored or obscure.

A fitting new name, for someone who was barely able to stay in the world anymore.

The plan had been to INJECT monsters with determination, not take it away.

So naturally, his current state was quite an unpredictable... well, predicament.

He certainly hadn't wanted his own son to be the first test subject of injecting the determination. But...

Circumstances suggested otherwise.

Sans couldn't understand him anymore. But that was fine. He was sure he could simply communicate through symbols.

That is, so long as he was able to stay in this world long enough to help his children continue without him.

And so, he let Sans SAVE Papyrus. Sans was intelligent. He would never do anything permanent to himself.

But a short length of time into their soul-sharing, Redacted began to suspect otherwise. After all, Sans' selflessness when it came to Papyrus was what caused the determination to be necessary in the first place.

And it was taking quite a long time...

His face literally melted into confusion, and he decided it may be best to simply CHECK the other.

*CHECK  
*SANS  
*HE REALLY LOVES HIS BROTHER.   
*ATK 1. DEF 1. HP-

Redacted melted into a puddle to move quicker across the floor, directly under Sans to restrain and hold him back. He pulled their souls apart quickly, a bit recklessly, but at this point it didn't matter. He pushed Papyrus' back into his chest and stared at Sans'. A small crack had formed in it, and he turned and glared at Sans. The child looked dazed, slowly coming back, and Redacted let out a stream of the static language he seemed to speak now.

“DO YOU HAVE ANY IDEA HOW DANGEROUS THAT WAS? HOW MUCH DANGER YOU JUST PUT YOURSELF IN? YOU HEALTH IS AT ONE NOW SANS. O N E . THE AVERAGE CHILD'S HEALTH IS 400, AT THE VERY L E A S T . I THOUGHT I COULD TRUST YOU, SANS, BUT APPARENTLY I CANNOT. I'M DISAPPOINTED.” 

He knew his son couldn't even understand him now, and he let out a large sigh.

He glitched out again.

“SANS. I CAN'T STAY IN THIS FORM FOR MUCH LONGER. PLEASE, PLEASE PROMISE ME YOU'LL TAKE CARE OF YOUR BROTHER- AND YOURSELF?” He said it panicky, forgetting once again the Sans couldn't understand him.

However, despite that, Sans' face scrunched and he hugged the mass. Perhaps it was how close he had come to death that allowed him to understand the other. 

Whatever the case, it didn't matter.

“I promise.” The small skeleton whispered it, barely audible, and Redacted smiled before he glitched out of the world entirely. Wherever he was was dark. Extremely dark. He couldn't see anything, in any direction. He settled himself into the area. 

He'd be staying there for a very long time, after all.

**Notes for the Chapter:**

> I tried to make Redacted/Gaster's speech in Wingdings but I'm unsure how to here sO  
> You may have it in regular English haha
> 
> The idea of Gaster falling into the DT Machine instead of the Core actually came from UndertaleBrokenHome on Tumblr a while back   
> I connected the dots that maybe an offset in Determination for any monster would turn them into an amalgamate, and the fact that Gaster's was EXTRACTED instead of INJECTED allowed me to do whatever I wanted with it.
> 
> In this case, I made it so it turned him into an amalgamate  
> There's more to it than that, but.  
> I'mma leave it there until I write more Gaster/Redacted junk in the future
> 
> Sans' promises are connected to a bad past.
> 
> The dust Sans chokes on in the beginning is actually Gaster's. I might not be elaborating on any of this so I'mma just say it here in case you get confused.
> 
> And dANGIT  
> I NEVER SEE REDACTED IN ANY HEADCANONS OR STORIES  
> I NEED MORE REDACTED HEADCANONS DUDE
> 
> FINALLY  
> The soul-sharing in this chapter is purely platonic, or at least Gaster means it to be, even if Sans isn't strictly platonic with his feelings for Papyrus at this point, and even if it turns not-so-platonic later on in their lives  
> GASTER IS NOT ENCOURAGING HIS SON TO ENGAGE IN SEXUAL ACTS WITH HIS OTHER SON WHEN THEY ARE THE AGES OF 8 AND 4 RESPECTIVELY


	3. I Would Do Anything

**Notes for the Chapter:**

> SMUTTY WERBENJAGGER

Sans bolted up from the bed, sweating. It took a few minutes of silence before he let out a sob. He hated this. He hated all of it. 

He hated missing his father.

And he hated-

He hated the heat that was building inside him, simply seeming to have the purpose of making him even more miserable.

Goddammit.

Papyrus must have triggered his own heat. Sans couldn't blame him for it. His mate's scent was simply... irresistable. And the fact that Papyrus' heat had been dominant...

Of course his would end up submissive.

He pulled his knees toward himself, rocking back and forth as he fought off his own urges. His urges to immediately seek the other out. To beg him...

It didn't matter what he wanted.

The tall skeleton probably wanted nothing to do with him right now.

Sans sighed, massaging his ribs to take some of the heat away, but it only intensified. Truth be told, he had masturbated on his own before, but the fact that he had never experienced a heat...

Well, it was a whole new feeling.

Sans let out little pants of need as he continued on his way along his ribs. They were extremely sensitive, perhaps entirely caused by the scar from long ago, or something else hidden to him completely. Regardless, it was certainly a place to go after on his heat.

'Of course you're being greedy.' Sans' hand stilled as his own thoughts filled his head. 'Instead of helping Papyrus through his first heat, you're here touching yourself. He's probably worse than you right now. He doesn't even know HOW to touch himself, you never showed him! Never even told him how heats worked...'

He tried to rationalize.

'Because I didn't want it to be an awkward conversation!'

'Because you had to spare your own feelings. You had to be greedy, keep knowledge all to yourself. Knowledge that could have helped him.'

The dark thoughts swirled in his mind.

'You know how dangerous they can be. Left unattended. That's why you only have one when you have a partner to handle it with you. It's dangerous, sometimes even deadly otherwise-'

“SHUT UP, I ALREADY KNOW!” Sans screamed it and panicked inwardly as he tried to determine whether Papyrus had heard him from the other room or not. Their walls were fairly thin, it wouldn't be hard...

After a moment of ringing silence, he sighed thankfully. Papyrus hadn't heard...

He frowned. Perhaps that wasn't the best of possibilities. It would have been simple to hear. How much... how far... 

How long had Sans been asleep? 

Long enough for his brother to progress to a stage where he couldn't even think coherently? Or had his brother left the house? Sans shook his head. Leaving wouldn't make sense, not to his muddled mind when his lover was in the house itself.

The small skeleton cursed his brother's stubbornness. It had to be painful by now, and yet he still had come back in to ask Sans for help...

Did he really hate the scar that much...?

Sans ran his fingers over it once more before shaking his head. It didn't matter whether he hated it or not, he wasn't going to risk his brother's health just because he had an old wound.

He breathed deeply before crawling off of his bed. His legs were already too weak to walk. Crawling up the door, he opened it slowly-

Only to be assaulted with the smell of caramel. 

It sent a pulse of arousal through him, but also fear- unfortunately for him, the fear amplified the arousal more and he collapsed to the ground with a thud. He laid there, glaring at the wood of the railing before doing an army crawl to his brother's room.

'You would do anything for Papyrus.'

He opened the door.

'Even if that means...'

He was drowned in the smell of caramel.

'Being his own personal sex toy.'

His brother pounced on him.

Sans was attacked with licks and bites before he had even hit the ground, his brother grinding into him heedlessly. Sans pushed him away slightly. He caught a glimpse of his face. Narrowed eyes, his right was flaming orange. His tongue was summoned and he panted, flushed, still pushing back into Sans. 

Sans was unable to hold the other back, and Papyrus bit his neck HARD, beginning to scrabble at his ribs, sending jolts of pleasure up the small skeleton's spine. The dominant skeleton pulled back for only a moment to look at the shirt in his way before tearing it off to each side of him. 

The sight of the scar gave him another pause and the flame in his eye died down slightly. Fear flickered across Sans' frame. If he still couldn't accept it, even in this state, than how could Sans even help him...?

Papyrus leaning down interrupted his train of thought, and he watched carefully as the other seemed to examine the very top of the wound before looking upward at Sans and licking across it, smirking as Sans jumped and grabbed at his head, letting out a moan.

It obscured Papyrus' vision of his face.

The taller skeleton grabbed both of Sans' wrists with one of his hands, licking across his hands slowly while maintaining eye contact with the other, a burning orange flame, before pinning them above his head and resuming licking, leaving no rib or area of the old wound completely free from the liquid of his tongue. As he did so, his other hand inched its way downward to Sans' pelvis, rubbing along each of his vertebrae, and he stuck it down his pants, teasing with the bones.

Sans was positively writhing at this point, legs twitching and flailing a bit to Papyrus' sides.

He was a natural.

One could argue that it was only because of his heat, telling him what he needed to do, but Sans wouldn't care.

His own heat begged for more anyway.

Sans' own scent grew stronger with each second, the smell of mulberries.

Papyrus was only encouraged more at the new addition, tongue flicking between Sans' ribs, nearly touching his soul but always pulling back out of his ribcage just before doing so, and Sans bounced, letting out a frustrated hiss before a sudden pause. It was suddenly colder than before.

Papyrus' tongue worked its way downward towards his now bare pelvis, shorts having already been pulled off and thrown to the side. He licked languidly down Sans' spine, staring into his eyesockets as he went downward, and Sans began quivering.

It suddenly hit him that neither of them had done this before.

He panted, still uncomfortably aroused yet terrified as Papyrus arrived at his pelvis, directing all of his attention to that.

What if it hurt too much? What if Sans had to call an end to it? Would Papyrus even stop, in the state that he was in...?

Sans shook his head mentally. It didn't matter how scared he became. Papyrus was more important. 

He always had been.

So, he waited tensely for the other to continue.

Papyrus tenderly licked at his cockyx, smirking upward towards him to see his expression. But something was different now...

“Sans...?” He couldn't pull himself fully away. He could be imagining it, after all, and then it would have been for nothing. The heat continued to cloud his vision and judgement even worse now than when his brother had entered, but he refused to do anything to hurt him. He had to be sure this was okay. What if he were doing something wrong? “It's your job to inform me if I have made a mistake.”

Sans stared at him blankly for a moment, arms still pinned, before letting out a chuckle. “nah bro. keep going. you're doing perfect.” He felt bad for ever having doubted Papyrus. He was that perfect, after all. He wouldn't do anything to hurt him.

The tall skeleton smiled before resuming his licks with even more enthusiasm than before. The area was sensitive now, and Sans jumped, legs clenching automatically around his brother's head. 

Papyrus pulled away slightly as a little blue organ appeared in front of him, looking at it curiously. It smelled strongly of mulberries. He reached his free hand upward and touched it gently, running his finger through the folds. The yelp from Sans, quickly muted, was enough to make him grin again, and he leaned his face towards it, licking through the mound. It tasted like mulberries as well. Finding a little hole farther down, he poked his tongue into it, puzzled. How far did it go? 

Sans' shaking and small noises continued, and Papyrus made his tongue longer, reaching in further- further, while he rubbed at the little bump in the center of it all with his hand softly.

The inside of the organ suddenly clenched around Papyrus' tongue and Sans let out a much louder moan than before. Liquid poured out of the hole and the skeleton licked it up quickly. Sans' legs twitched along with his magic, and he let out little whimpers as Papyrus cleaned the area with a hum. 

Once the liquid itself was mostly gone, Papyrus noticed a slight pain near his own pelvis, and he pulled Sans' legs away from his head, pulling away to check what it was.

He pulled down his own shorts to see he had formed something with his own magic, a long orange rod.

Sans looked down at it with a longing gaze. 

“What is it for?” Papyrus spoke quietly to him.

The blatant question made Sans flush even more and he averted his gaze. “you... uh, put it inside...”

The taller skeleton stared down at the hole, wondering why he hadn't thought about it. Maybe it was the fact of how Sans looked, the corner of his eyes filled with tears and the blue dusting his cheekbones wouldn't have helped his thoughts.

He rubbed the tip of the member against Sans' entrance, hissing a bit at the pleasure it created. It was so much better than what he'd had so far. Gauging Sans' own reaction, he slowly pushed in.

The grunt of pain gave him alarm, but Sans made no protests, turning his gaze back to his lover. His pupils had turned to hearts and Papyrus couldn't help but simply love him more. 

The heat was invading his mind once more.

He pulled out slowly before slamming in much harder than before. Sans' entire body tensed up against it, and his legs wrapped around Papyrus' hips. “d-do it again, please paps-”

So he did. Outward slowly, inward quickly, over and over until outward wasn't going slowly anymore and he was pounding into the small skeleton's body. His member went all the way up to the bottom of Sans' ribs. Quite a sight.

After a minute, Sans was incoherently begging for more and Papyrus was panting heavily, a pressure growing in his abdomen. It felt strange, but it was a good strange. Like he would simply explode from the pleasure if this continued.

It only took half a minute more before Sans came a second time, screaming out Papyrus' name. He understood why the walls clenched now. The sudden pleasure caused his own to rippled through him, shakily continuing to thrust before stopping completely. 

He pulled out of the other slowly, not certain if he'd ever felt this tired in his entire life. 

All of those worries were quickly washed away though by the look on his brother's face. 

He would do anything for that expression.

He nuzzled against Sans' cheekbone happily, contentedly, picking him up and bringing him back into his room, shutting the door behind him.

The heat wasn't completely gone.

Tonight was going to be very fun indeed.

**Notes for the Chapter:**

> EHHHHHH  
> BETTER THAN MY LAST ATTEMPT AT NSFW WRITING  
> STILL NOT GREAT   
> BUT IT'S AN I M P R O V E M E N T  
> Anyway, I'm thinking about taking a break for a while because this one took me wAYYYYY TOO LONG TO WRITE  
> FOR SOMETHING THAT DIDN'T EVEN TURN OUT THAT GREAT  
> So idk how long that break may be  
> a day  
> a week  
> forever  
> idk with me it just really fluctuates  
> sO I F I GO MISSING FOR A WHILE DON'T WORRY ABOUT IT  
> YOU'LL PROBABLY STILL FIND ME GIVING KUDOS TO SOME OF THE NEWER FONTCEST FICS  
> i may have an obsession ok  
> don't u judge me  
> u came in and read this crap  
> ANYWAY BAD CONCLUSION SEEYA ALL LATER

**Author's Note:**

> First smut fic and I accidentally make it emotional w h oop s  
> it's okay  
> next chapter will be better  
> probably  
> ok but i actually was just intending on practicing smut for the first time  
> but apparently my hands don't wanna make it that simple???  
> So uh  
> Hope you enjoyed so far ^^  
> Also any tips?  
> I've never written a full story before honestly  
> These fics are the first things  
> SO  
> TIPS ON PACING WOULD BE REALLY NICE  
> BECAUSE IT SEEMS LIKE EVERY TIME I PROOF-READ ANYTHING IT SEEMS W A Y TO O FAST


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